Tamil is the first language of the majority of the people residing in Tamil Nadu in India and Northern Province, Eastern Province, Sri Lanka. The language is also spoken among small minority groups in other states of India which include Karnataka, Andhra Pradesh, Kerala, Maharashtra and in certain regions of Sri Lanka such as Colombo and the hill country. Previously Tamil had a wider distribution in India than its current state. Tamil or dialects of it were used widely in the state of Kerala as the major language of administration, literature and common usage until the 12th century CE. Tamil was also used widely in inscriptions found in southern Andhra Pradesh districts of Chittoor and Nellore until the 12th century AD.

There are currently sizeable Tamil-speaking populations descended from colonial-era migrants in Malaysia, Singapore, Mauritius,((Seychelles)), South Africa, Indonesia, Thailand, Burma, and Vietnam. Many in Réunion, Guyana, Fiji, Suriname, and Trinidad and Tobago have Tamil origins, but only a small number speak the language. In Reunion where Tamil language was forbidden to be learnt and used in public space is now being relearnt by students and adults. It is also used by groups of migrants from Sri Lanka and India in Canada (especially Toronto), USA (especially New Jersey and New York City), Australia, many Middle Eastern countries, and most of the Western European countries. Tamil is also spoken in Norway, Germany, United Kingdom, Ireland and other European countries.